Shipping Bag Split-Film Closure for Tamper-Evident Opening

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Solution Overview

Problem

Existing shipping bags, particularly those made of paper, lack reliable mechanisms to prevent unauthorized opening and ensure a standardized, stable opening, while plastic bags often require complex perforation lines that are not applicable to paper bags.

Innovation Solution

A shipping bag design featuring multiple folds and weakening lines, combined with an adhesive strip, ensures secure closure and irreversible separation upon opening, utilizing a split film that delaminates into distinct components upon separation, creating unique delamination patterns to prevent re-use.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If paper bags are used for shipping, then cost-effectiveness and environmental friendliness are improved, but reliable protection against unauthorized opening and moisture is lost

Engineering Contradiction:
Improvecost-effectivenessVSAvoidprotection against unauthorized opening
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The adhesive strip is divided into multiple segments separated by weakening lines. When the bag is opened, these segments separate cleanly along the weakening lines, creating visible evidence of opening while maintaining the integrity of the adhesive bonding material itself. This segmentation allows paper bags to achieve tamper-evident functionality without requiring complex structures.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The adhesive strip is pre-applied to the bag during manufacturing, and the weakening lines are pre-formed in the adhesive layer. This preliminary preparation ensures that when opening is attempted, the adhesive segments separate cleanly along predetermined paths, providing reliable tamper evidence before the actual opening occurs.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If adhesive strips are added to paper bags for secure closure, then closure reliability is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improveclosure reliabilityVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The tamper-evident functionality is extracted as a separate feature within the adhesive strip structure. The weakening lines create distinct segments that can separate independently, allowing the adhesive to provide both bonding and evidence functions without requiring additional components or complex mechanisms.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The adhesive strip has non-uniform properties: strong adhesive bonding in most areas, but localized weakness along the weakening lines. This local variation in adhesive strength allows the strip to maintain overall bonding reliability while providing predetermined separation paths for tamper evidence.

Inventive Principle:
Principle #3Local quality

3Ease of operation

If perforation lines are used to facilitate opening, then ease of operation is improved, but standardized opening position and size are not ensured

Engineering Contradiction:
Improveease of openingVSAvoidopening position standardization
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The weakening lines serve multiple functions simultaneously: they act as perforation lines for easy opening, define the precise position and size of the opening aperture, and provide tamper-evident separation paths. This multi-functionality eliminates the need for separate features for each purpose.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The opening path is pre-defined by the weakening lines during manufacturing. Users simply need to tear along these predetermined lines, which automatically create a standardized opening of specific position and dimensions, eliminating variability in opening characteristics.

Inventive Principle:
Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The design provides a cost-effective, secure closure that prevents accidental opening and unauthorized reuse, with distinct delamination patterns ensuring easy detection of tampering.

Implementation Method 1

comprising a bag front wall and a bag back wall, which are connected to each other at least partially, preferably completely, directly or indirectly, in particular via at least one wall

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP3511259B1Bag, in particular shipping bag with at least one adhesive
Publication Date: 2026.03.04 PAPIER METTLER
  • EP3511259B1 patent drawingFigure 1
  • EP3511259B1 patent drawingFigure 2
  • EP3511259B1 patent drawingFigure 3~4

AI summary

The invention relates to a bag with a first and second folding section for closing the opening with an adhesive, in particular with a split film. The invention also relates to a bag with an adhesive comprising a split film, which is designed and configured to irreversibly split into at least a first component of the split film on the front wall of the bag and at least a second component of the split film on the back wall of the bag when the front and back walls of the bag are separated, in the area of ​​the split film, in particular wherein the first component is irreversibly delaminated from the second component. The invention further relates to the use of such bags for shipping food.